1. Field of the Invention
This invention relates, generally, to improvements in air conditioning systems. More particularly, it relates to an apparatus for quickly pressurizing a chiller for maintenance purposes.
2. Description of the Prior Art
Air conditioning systems are a well known source of compounds that cause depletion of the ozone layer; thus, system operators can be fined for operating systems that leak harmful compounds into the atmosphere. Leaks are usually found by taking the chiller out of service and pressurizing it; leak detection when the system is operating is impractical because the chiller evaporator operates at less than atmospheric pressure. There is insufficient time to check for leaks during summer daylight hours when maintenance crews are available because the leak-testing procedure is very time-consuming and most systems cannot remain inoperative for the required amount of time.
Routine preventative maintenance is therefore performed on air conditioning system chillers usually about once a year, typically during the winter months when the demand for air conditioning is low. The maintenance procedures include pressurization of the chiller so that it may be tested for leaks as aforesaid and so that oil in the sump may be removed and replaced.
Chillers are pressurized by heating water in the evaporization circuit of the chiller; this raises the temperature of the refrigerant and thus enables the system to be checked for refrigerant leaks and enables oil removal as aforesaid. Current practice employs conventional hot water heaters and pumps to heat the water and to circulate it. The process requires several hours for small chillers, and can take all day where a large chiller is involved. The maintenance crew must wait for the pressurization to be completed before the leak testing and oil changing procedures can be started. Thus, the cost of the procedure is quite high.
What is needed, then, is an apparatus that quickly pressurizes a chiller. Such a system would free the maintenance crew for other tasks and would be less expensive for the system operator. However, the conventional technique is the only obvious way to perform the task because those of ordinary skill in the art have been performing the conventional technique for decades and have been unable to improve upon it even though the need for improvement is apparent to everyone in the art.